KR101479709B1 - Sensor and method for measuring tactile information - Google Patents

Abstract

The present invention relates to a contact information measuring sensor, and a contact information measuring sensor of the present invention includes a sensor portion divided into a first sensing surface having a spherical surface and a second sensing surface having a surface of an aspherical surface; A measuring unit for measuring a force or a torque applied to the sensor unit by an object; And a position calculating unit for calculating a position at which the object contacts the sensor unit from the information measured by the measuring unit, assuming that the surface of the sensor unit is either spherical or aspheric.
Therefore, according to the present invention, a contact information measurement sensor capable of measuring the strength of a contact force and the position of a contact point applied to a complex structure-type sensor to which various structures are coupled can be reliably measured.

Description

Technical Field [0001] The present invention relates to a contact information measuring sensor and a contact information measuring method,

The present invention relates to a contact information measuring sensor, and more particularly, to a contact information measuring sensor capable of measuring a contact force and a contact point by an object.

Research to achieve the same mechanism as the human body is a global concern. In particular, efforts to develop humanoid hands have been concentrated at home and abroad, in order to represent the performance of tasks in dangerous or difficult places to be directly performed by people.

However, since human hands include about 30 bones in spite of a small volume compared to other bodies, delicate movements are possible, so that it is difficult to realize such human-like movements as robots.

In particular, in order to fully simulate the human hand in addition to such a multi-degree-of-freedom operating mechanism, a technique is required to be able to sense the same touch as the human touch.

To this end, a sensor has been developed in which a contact force by an object is detected by being attached to the end of a finger of a robot hand. Such conventional sensors measure the contact force and the torque applied to the outer surface using a strain gauge.

In addition, studies for checking the contact points of objects using the contact force and torque intensity information are also continuing. According to the conventional research, it is possible to calculate the contact point only when the shape of the sensor structure contacting the object is constant, such as spherical shape or cylindrical shape, using the contact force information.

However, in the case of a structure in which various shapes are combined, there is a problem that reliability of the contact point position calculated through the contact point estimation method of the conventional art is low due to a large error with the actual contact point.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the problems of the prior art described above, and it is an object of the present invention to provide a contact type sensor which can measure the contact force, Sensor.

According to the present invention, A measuring unit for measuring a force or a torque applied to the sensor unit by an object to be contacted; And a position calculating section for calculating a position at which the object contacts the sensor section from information measured from the measuring section, assuming that the shape of the surface of the sensor section is either spherical or aspherical. This is accomplished by a measurement sensor.

The surface of the sensor unit may be divided into a first sensing surface of a spherical surface and a second sensing surface of an aspheric surface and may be provided on either the first sensing surface or the second sensing surface, And the position calculating section is provided with the contact information of the object from the contact determining section and assumes that the surface of the sensor section is spherical when the object contacts the first sensing surface, The position of the object can be calculated assuming that the surface of the sensor unit is an aspherical surface.

In addition, the sensor unit may have a receiving space formed therein, the measuring unit may include a sensing frame installed in the receiving space and connected to the inner surface of the sensor unit. And a strain gauge connected to the sensing frame and measuring a strain amount of the sensing frame.

The position calculating unit may include a first determining module that determines a position of an object contacting the sensor unit on the assumption that the surface of the sensor unit is a spherical surface; And a second determination module for determining a position of an object contacting the sensor unit on the assumption that the surface of the sensor unit is an aspherical surface.

The contact determination unit may include a plurality of electrodes spaced apart from each other on either the first sensing surface or the second sensing surface; A dielectric elastomer provided between adjacent electrodes; And a detector for measuring a change in a capacitance value between the electrodes to determine whether the object is in contact with the object.

The contact determination unit may include: an electrode disposed on one of the first sensing surface and the second sensing surface; And a detector for measuring a change in resistance value of the electrode and determining whether the object is in contact with the electrode.

According to another aspect of the present invention, there is provided a method of measuring a force or torque applied to a sensor unit, the method comprising: measuring a force or a torque applied to the sensor unit from an object to be contacted; And calculating a contact point of the object by assuming that the sensor unit is either spherical or aspherical depending on the shape of the surface of the sensor unit with which the object is contacted do.

According to the present invention, there is provided a contact information measuring sensor capable of accurately detecting a position of a contact point using intensity information of a contact force.

Further, after the position of the approximate contact point is determined in advance through the contact determination section, an accurate contact position determination can be performed by selectively applying an algorithm for calculating the point touch point according to the approximate position of the contact point.

Also, by using the dielectric elastomer to determine the approximate position of the contact point through the change of the capacitance value, the contact determining part can improve the gripping ability of the object when applied to an actual robot hand using the surface friction force of the dielectric elastomer.

FIG. 1 illustrates a humanoid robot hand on which a contact information measurement sensor according to a first embodiment of the present invention is mounted,
Fig. 2 is a schematic perspective view of the contact information measuring sensor of Fig. 1,
FIG. 3 is an exploded perspective view of the contact information measuring sensor of FIG. 1,
Fig. 4 is a view for explaining the operation of the contact information measuring sensor of Fig. 1,
5 is a schematic perspective view of a contact information measurement sensor according to a second embodiment of the present invention.

Prior to the description, components having the same configuration are denoted by the same reference numerals as those in the first embodiment. In other embodiments, configurations different from those of the first embodiment will be described do.

Hereinafter, a contact information measurement sensor 100 according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic perspective view of a contact information measuring sensor of FIG. 1, FIG. 3 is a perspective view of a contact information measuring sensor according to a first embodiment of the present invention, Fig. 3 is an exploded perspective view of the information measuring sensor. Fig.

1 to 3, the contact information measuring sensor 100 according to the first embodiment of the present invention measures the contact point of the object, that is, the contact position, using the force and torque information applied by the object And includes a sensor unit 110, a contact determination unit 120, a measurement unit 130, and a position calculation unit 140.

The sensor unit 110 includes a first sensor unit 111 and a second sensor unit 113 to provide a surface on which an object is directly brought into contact.

The first sensor unit 111 has a structure in which a spherical structure is divided into a quarter, and a space is formed therein. The surface of the first sensor unit 111 is a region in which direct contact with an object occurs. The surface of the first sensor unit 111 formed as a spherical surface is defined as a first sensing surface 112.

The second sensor unit 113 is connected to the first sensor unit 111 and has a shape in which a cylindrical structure is divided into two parts. Like the first sensor unit 111, do. The surface of the second sensor portion 113, that is, the surface connected to the first sensing surface 112, is a region where direct contact with an object occurs, and is formed as an aspheric surface and defined as a second sensing surface 114 do.

Therefore, the sensor unit 110 having a structure in which the first sensor unit 111 and the second sensor unit 113 in which a space is formed are mutually connected is provided with the first sensing surface 112 of the spherical surface and the second sensing surface 112 of the aspheric surface, The surface 113 is continuously connected, and a receiving space is formed therein.

The first sensor unit 111 and the second sensor unit 113 may be separately formed and then joined to each other or may be integrally formed to improve the overall durability of the sensor unit 110 It is possible.

The contact determination unit 120 is provided on the second sensing surface 114 to determine whether or not an object has contacted on the second sensing surface 114. The contact determination unit 120 determines the contact between the electrode 121 and the dielectric elastomer 122, And a detection unit 123.

The electrodes 121 are spaced apart from each other in the form of a plurality of stripes, and a dielectric elastomer 122, which will be described later, is provided in the spaced apart spaces.

The dielectric elastic body 122 is an elastic body having a dielectric constant, and is disposed between the above-described electrodes. Also, it is preferable that the dielectric elastomer 122 used in the present embodiment is flexible, has a predetermined permittivity, and is made of a material having a large coefficient of friction in order to prevent slip upon contact with an object.

The structures of the plurality of electrodes 121 and the dielectric elastomer 122 are preferably disposed on the entire surface of the second sensing surface 114, but the present invention is not limited thereto.

The detection unit 123 detects a change in capacitance value from the electrode 121 and the dielectric elastomer 122 disposed therebetween to determine whether contact between the second sensing surface 114 and the object has occurred .

In the present embodiment, the contact determination unit 120 is disposed on the second sensing surface 114. However, when the contact determination unit 120 contacts the sensor unit 110, 1 sensing surface 112 or the second sensing surface 114. The sensing surface 112 may be disposed on the second sensing surface 114 instead of the first sensing surface 112. [

The measurement unit 130 measures a force or a torque applied to the sensor unit 110 and includes a sensing frame 131 and a strain gauge 132.

The sensing frame 131 is accommodated in a receiving space formed in the sensor unit 110 and is connected to the inner wall surface of the sensor unit 110 so that the sensing frame 131 is physically deformed due to the contact force applied to the sensor unit 110. [ to be.

The strain gage 132 is connected to the sensing frame 131 to measure the amount of deformation of the sensing frame 131 and measure the force or torque applied to the sensor unit 110.

The position calculating unit 140 is used to calculate a contact point, i.e., a contact point, by using only the force and torque information measured by the measuring unit 130. The position calculating unit 140 includes a first determining module 141 and a second determining module 142).

The first determination module 141 is a module for calculating the position of the contact force applied to the sensor unit 110 on the assumption that the shape of the entire surface of the sensor unit 110 is spherical.

The second determination module 142 is a module for calculating the position of the contact force applied to the sensor unit 110 on the assumption that the shape of the entire surface of the sensor unit 110 is aspherical.

That is, the main position calculating unit 140 determines whether the contact force is applied to the first sensing surface 112, which is a spherical surface, or the second sensing surface 114, which is an aspheric surface, through the contact determination unit 120 If it is determined that the contact is applied to the first sensing surface 112, the position of the contact point is calculated through the first determination module 141 on the assumption that the entire shape of the sensor portion is spherical, 2 sensing surface 114, the position of the contact point is calculated on the assumption that the shape of the entire sensor portion 110 is a cylindrical shape through the second determination module 142.

In a paper titled Intrinsic contact sensing for soft fingers (Robotic and Automation, 1990 IEEE Internationa Conference) as an example of calculating the position of such a contact point, a calculation method as shown in the following [Equation 1] to [Equation 3] Respectively.

(Where c is a matrix representing the position of the contact point, f is a force vector measured from the measurement unit, m is a moment vector measured from the measurement unit, A is a matrix indicating the shape of the sensor unit, D is det Means a scale factor determined depending on the size of the sensor unit.)

Further, the K value and the Γ value in the above-described expression (1) can be expressed by the following equations (2) and (3).

Hereinafter, the operation of the first embodiment of the contact information measuring sensor will be described.

Fig. 4 is a view for explaining the operation of the contact information measuring sensor of Fig.

First, referring to FIG. 4 (a), a case where a predetermined contact force is applied to the second sensing surface 114 will be described as an example.

When the contact force is applied to the second sensing surface 114, the sensing frame 131 installed in the receiving space of the sensor unit 110 is deformed and the strain gage 132 is deformed by the sensing frame 131 , And the force and torque applied to the second sensing surface 114 are measured.

The gap between the electrodes 121 provided on the second sensing surface 114 is reduced by the applied force to change the capacitance between the electrodes 121. The detection unit 123 detects the capacitance between the electrodes 121, A change in the capacitance value between the input terminal and the output terminal is detected. Accordingly, the contact determination unit 120 determines that a contact has occurred on the second sensing surface 114. [0051] FIG.

According to the information of the contact determination unit 120, the position calculation unit 140 calculates the position at which the contact force is applied using the second determination module 142. [ That is, in order to reduce the error, it is assumed that the shape of the sensor unit 110 is cylindrical (cylindrical), and using the algorithm optimized for calculating the position information using the force and torque information applied to the cylindrical shape, The position of the contact force is determined.

That is, assuming that the entire sensor unit 110 is cylindrical, the value of the matrix c indicating the position of the punctual point in Equation (1) can be summarized as Equation (4) below.

Next, referring to Fig. 4 (b), a case where a predetermined contact force is applied to the first sensing surface 112 will be described as an example.

When the contact force is applied to the first sensing surface 112, the sensing frame 131 installed in the receiving space of the sensor unit 110 is deformed and the strain gage 132 is deformed by the deformation of the sensing frame 131 , The contact force applied to the second sensing surface 114 is measured.

When the contact force is applied to the first sensing surface 112, the capacitance between the electrodes 121 provided on the second sensing surface 114 does not change, It is judged that the contact has not been made.

Therefore, the position calculating unit 140 calculates the position at which the contact force is applied by using the first determination module 141, based on the contact information detected by the contact determination unit 120. [ That is, in order to reduce the error, it is assumed that the shape of the sensor unit 110 is spherical, and the position of the applied contact force is calculated by using an algorithm optimized for calculating the position information using the force and torque information applied to the spherical shape .

That is, assuming that the entire sensor unit 110 is spherical, the matrix c value indicating the position of the punctual point in Equation (1) can be summarized as Equation (5) below.

Therefore, according to the present embodiment, the reliability of the calculated contact point position can be improved by applying the contact point calculation algorithm applied in accordance with the surface shape of the approximate position to be contacted.

Next, a contact information measurement sensor according to a second embodiment of the present invention will be described in detail.

5 is a schematic perspective view of a contact information measurement sensor according to a second embodiment of the present invention.

5, the contact information measurement sensor 200 according to the second embodiment of the present invention includes a sensor (not shown) that can precisely measure the contact position of an object, using force and torque information applied by the object, And includes a sensor unit 110, a contact determination unit 220, a measurement unit 130, and a position calculation unit 140.

Since the sensor unit 110, the measurement unit 130, and the position calculation unit 140 are the same as those described in the first embodiment, redundant description will be omitted.

The contact determination unit 220 is disposed on the second sensing surface 114 to determine whether or not an object has contacted the second sensing surface 114. The contact determination unit 220 determines whether the contact of the object has occurred, .

The electrode 221 is electrically conductive and is disposed on the second sensing surface 114 and is disposed on the entire surface, but is not limited thereto.

The detection unit 222 detects a change in resistance value of the electrode 221 and determines whether a contact between the second sensing surface 114 and an object has occurred.

Therefore, in this embodiment, unlike the first embodiment, the resistance value change of the electrode 221 is measured to determine whether or not the contact force is applied to the second sensing surface 114.

In the first and second embodiments of the present invention described above, the method of calculating the position of the contact point has been described as the method disclosed in [the paper], but the position of the contact point is calculated using the contact force and the torque to be measured The method is not limited thereto.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

110: sensor unit 120: contact determination unit
130: Measuring unit 140: Position calculating unit

Claims (7)

A sensor unit having a first sensing surface whose surface is spherical and a second sensing surface which is an aspheric surface;
A measuring unit for measuring a force or a torque applied to the sensor unit by an object to be contacted;
A contact determination unit provided at any one of the first sensing surface and the second sensing surface to determine whether an object is in contact with the object; And
A position calculating unit for calculating a position at which an object contacts the sensor unit using the information measured by the measuring unit and the contact determining unit;
And,
Wherein the sensor unit has a receiving space therein, the measuring unit includes a sensing frame installed in the receiving space and connected to the inner surface of the sensor unit, And a strain gauge connected to the sensing frame to measure a deformation amount of the sensing frame, wherein the position calculating unit is provided with contact information of an object from the contact determining unit, wherein when the object is in contact with the first sensing surface And the position of the object is calculated on the assumption that the surface of the sensor unit is spherical and the surface of the sensor unit is aspherical when the object is in contact with the second sensing surface. sensor. delete delete The method according to claim 1,
The position calculating unit may include a first determining module for determining a position of an object contacting the sensor unit on the assumption that the surface of the sensor unit is a spherical surface; And a second determination module for determining a position of an object contacting the sensor unit, assuming that the surface of the sensor unit is an aspherical surface. The method according to claim 1 or 4,
The contact determination unit may include a plurality of electrodes spaced apart from each other on either the first sensing surface or the second sensing surface; A dielectric elastomer provided between adjacent electrodes; And a detector for measuring a change in a capacitance value between the electrodes to determine whether or not an object is in contact with the contact information sensor. The method according to claim 1 or 4,
Wherein the contact determination unit comprises: an electrode disposed on one of the first sensing surface and the second sensing surface; And a detector for measuring a change in a resistance value of the electrode to determine whether or not an object is in contact with the contact. A contact information measuring method using the contact information measuring sensor of claim 1 or 4,
Measuring a force or a torque applied to the sensor unit from an object to be contacted;
And calculating a contact point of the object on the assumption that the sensor unit is either spherical or aspherical depending on the shape of the surface of the sensor unit in contact with the object.

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